Kate of turn indicator



July 6, 19418. J. E. BEVINS I RATE OF TURN INDICATOR 3 Sheets-Sheet 1Filed March 15, 1943 July 6, 1948.

Filed Ma'rqh 15, 1943 J. E. BEVINS RATE OF TURN INDICATOR 3 Sheets-Sheet3 INVENTOR BY b tes E Beyb s.

ATTORNEY Patented July 6, 1948 RATE OF TURN INDICATOR James E. Bevins,Hackensack, N. J., assignor to Bendix Aviation rporation, Bendix, N. J.,a corporation of Delaware Application March 15, 1943, Serial No. 479,263

8 Claims.

This invention relates to turn indicators for indicating angularmovement of a mobile or dirigible vehicle about oneof its axes, and moreparticularly to novel damping means therefor.

In known turn indicators, such as that represented by Patent No.2,010,191 issued to P. W. Koch et al. on August 6, 1935, and assigned tothe assignee of the present application, it has been the practice toconnect the gyroscopic element directly to the indicator and providesome form of yieldable restraining means acting upon the directconnection to stabilize the indicator. Although such provisionconstituted a partial solution of the problem, nevertheless, when choppyflying conditions prevailed, gimbal oscillations occurring as a resultof rough flying were transmitted, in part at least, through the directconnection to the indicator so that its reading proved blurred andtherefore unreliable.

It is an object of the present invention, therefore, to overcome theforegoing disadvantages by providing an improved turn indicator havingnovel damping means therefor.

Another object of the invention is to provide an improved turn indicatornection in the form of a yieldable coupling between the gyroscopicelement and the pointer thereof whereby the pointer will besubstantially stabilized, notwithstanding gimbal vibration resultingfrom undesirable flying conditions.

A further object of the invention is to provide a turn indicator withnovel damping means in the form of a pair of opposed spring memberswhich act to transmit gyroscopic precession to a pointer resultingduring a craft turn and which also act to absorb undesirable gimbalvibrations occurring during the presence of rough flying conditions thusleavin the pointer substantially free of gimbal vibration.

Another object is to provide an improved instrument for the purposedescribed with novel damping mechanism adapted to stabilize theinstrument pointer against undesirable vibrations I as well as againstexcess movement and erratic action to thus insure reliable performance.

The above and other objects and advantages of the invention will appearmore fully hereinafter from a consideration of the detailed descriptionwhich follows, taken together with the accompanying drawings wherein oneembodiment of the invention is illustrated. It is to be expresslyunderstood, however, that the drawings are for the purpose ofillustration and description only and are not designed as a definitionof the limits of the invention.

having a novel concator may be viewed as In the drawings, wherein likereference characters refer to like parts throughout the several views,

Figure 1 is a front elevation view of one form of turn indicatorembodying the subject matter of the present invention;

Figure 2 is a vertical section view taken substantially along line 2-2of Figure 1;

Figure 3 is a vertical section view taken substantially along line 3-3of Figure 2;

Figure 4 is an exploded perspective view of the novel damping means ofthe present invention;

Figure 5 is a side elevation view of a of the structure of Figure 4; and

Figure 6 is a fragmentary detail view portion of the structure of Figure2;

Referring now to the drawings for a more de-' tailed description of thepresent invention, and more particularly to Figure 2 thereof, theinstrument comprises an airtight casing I0 having an enlarged portion II which is provided with an annular flange (Fig. 3) having lugs I2 thereon provided with screw receiving apertures I3 therein for mounting theinstrument on an instrument panel of an aircraft, for example, theangular motion of which is to be indicated, so that the longitudinalaxis of the casing will coincide with or lie parallel to thelongitudinal axis of the craft.

Gyroscopic apparatus is mounted in any suitable manner within the casingas by means of adjustable pivots I4, I5 and includes a gyro rotor I 6journalled in a gimbal I! for rotation about a horizontal axisperpendicular to the axis constituted by pivots I4, I5 in suitablebearings, one of which is shown at I8, so that the gimbal may oscillateabout axis I4, I5 due to the precessional forces acting thereon, whenthe gimbal and casing are turned about an axis perpendicular'to both ofthe first-mentioned axes.

A pointer I9 is provided for indicating the precessional movement of thegyroscope about axes I4, I5 and is carried by a shaft 2llyrotatablymounted in a supporting bracket 2| secured to portion II by suitablemeans, such as screws 22 (Fig. 3). The pointer is superimposed formovement over a dial 23 carriedby the casing and having an opening 24 atits lower end through which pointer shaft 20 is adaptedto extend. Dial23 is also provided with a transverse arouate slot 25 (Fig. 2) throughwhich a bank indiis well known-in the art.

A bezel 33' suitably closesthe' open end of-the instrument and supportsthereina" cover glass 34 portion ofa thetojfehdof the pinsin any othersuitable manner as, for example, by

connecting a suction pump (not shown) tooutlet 31.

After a precessional movement of the gyro rotor and gimbal, it isdesirable that both be returned to a normal and central position and, tothis end, novel means are provided'ion'centralizing gimbal l1 relativeto the casing about axis -lfl, l5 after the craft has completed a turn,the meansv being constructed and arranged in such a manner that besidescentralizing the gimbal it also servesas damping means for absorbinggimbal oscillation due to rough flying conditions,

for example, andthereby .prevent-the' transfer ot'undesirableoscillation, in amanner to "presently appear, to thelpointerso that'the latter is substantially stabilized to therebyprovide areliable reading.

To end, gimbal ll carries-a plate '38 which hasfastened thereto by meanssuch as spacers 33, '40. and screws] 1, 42, a bracket member43 providedwith two integrally formed arms 44' and 45 (Fig. 4). Supported at theextremity of arm'fl ilis a shaft which receivesa relatively movablesleeve member 41 secured to a lever48, the latterbeing provided withltwo" substantially diametric'arms 49- and.50 (Figures"3and '4'). Theouter endof shaftilfi is screw threaded f'or the reception of a nut 5ithereon which -holds-leverfl8 against longitudinal motionrelative tobracket 43. Shaft 36 d bracket 43, moreover, is arranged coaxiallywithtpr'ecessional ax-is l4,-l5 so that revolution of'thebracketandlever is always about an axis concentric withthe precessional axis.

.A finger'52 is fastened to -and'iprojects .outwardlyifr-om lever 48 andis arranged to be interinediatea pair of para1lelarms 53 and, 54 (Figi6) which are'supported by a Weightedblock "55, the latter having securedthereto the free end of pointershaft 20. h Motion in either/direction.on thepartof l'ever'lB "is transmitted to: pointer 19 by virtue of thearm and finger" connection.

( 1 In \order to transfer gimbal -motion in-.a. suitably dampedmannerfromibrack'et' 43 to lever '48, thebra'cketand lever are. provided,respectively, with two-rcooperating/ pins' 56 and '51,,pin 56b'einglfastened at-a substantially central portion tune bracketand .pin5i being fastened to lever arm 49. Bracket-43, furthermore, has fastenedthereto lugs 58 and 59,-each-ofwhichsupportsthe free endaof-one of twoopposi 'ely arranged centralizing-- l-spr-ings -63 and 5 I The free endof spring 60 'ishooked about thelbottom of pins 56, 51 whiletheireeend'ofspring 'fil is hooked over (Figifihso that the two springsdefine-the sole coupling or connection betweengir'nbal-ll and pointer19. With this novel arrangement (springs 60 and 6 I will. always returnthesgimb'aIQ following a precessional .movement, toa-normallycentralizedposition while,= during rough flying conditions, gimb'al os'oi-llationis absorbed-andL-damped .by thewsprings without being transferred to-1ever"48 so'.that. pointer l 9 remains substantiallystabilized.

5 cambemadeflinlthe design and arrangement of 'silientlyr constrainingprecession of. said element,

70 said driven member, and meansmcolfnprising' pp- !!5 gyroscopicelement mounted for precession in ac- In addition to the action ofcentralizing springs and 6| upon the gimbal, the motion of the latter isalso restrained yieldably by virtue of a calibration spring 62 (Fig. 3)which is secured 5 at one of its ends to arm 45 of bracket 43 and at itsother end is anchored to a block 63 mounted within casing l0 and soarranged as to be adjustable at will for .the initial calibration ofspring =62. This-spring acts through-bracket 43 to re- 10 strainprecessional motion of the gyro to a rate of turn function as is wellknown in the art of turn indicators.

-'Supplementing the action of springs 60 and Bi l-to furtherincreasethereliability of instrument indicationpanadditional damping means in the"form of -audash pot is provided and comprises a cylinder 64 having athreaded and hollow ex- *tension-member65'Which is received by easing l0(Figure 3) and secured thereto by virtue of a nut 66 accessible from theexterior of the casing. Mounted for reciprocal movement within the cyinder is a piston 61 which is, provided with a pivotallymounted;connecting lin'lcGB Securing the piston tciarm 50 of lever 48.

The cylinder head is in restricted communication'witnthe interior. ofthecasing by virtueof a vent BB'with whichlcooperates a valve in theform lOf a ithreadedmember'ln to vary the amount of the restriction andthus predetermine the amount of'damping, provided by the dash-pot. Byvirtue of such'dash-poaupward movement oi the piston is, yieldablyrestrained because air 'flow from the cylirider is. metered throughventfit and downward motionislikewisedamped' since in this case airlfiow.into" the cylinder\ is metered so that a su'ctionis created above thepiston. In this mannerunotionlofl lever. 48 and, therefore, motion ofpointer 19 through springs 60 andBl' .is yieldably constrained by the.dash-pot .andgimbal motion 0 itself .isdamped. before being-transmittedto the pointerland also motion due to oscillation. of the gimbalresulting; from choppy weather is eliminated without afiecting'thepointer.

An improved damping means hasbeen thus providedLin whichfthelgimbaldrives both the damping piston andicylinder assembly, and the pointerthrough two relatively small centralizing, springs 68 and BI; which-aremounted in such-a manner that they centralize thepointenand gimbal after50 the completionof arcrait turn.

4 Although bntva single embodiment of thepresent' inventionhasbeen'illustrated and described in detaihit is to be expresslyunderstoodthat the invention :is not limited thereto. Various changesparts without departing from the spirit and scope ofl'the invention, aswill now beunderstood by those skilled in, the art. For a;definit'ron ofthe limits of the invention, reference willbe had primarily to theappended claims.

I claim:

."A "turn indicator for aircraft comprising a ,gyroscopic elementmounted forprecession in accordancewith the rate of craft turn," meansrean indicator, adriven. member for actuating said indicator, meansconstraining movement of? said drivenrmerhbery a ,driving memberactuated vby s'a'i'd .r'otor. precession land pivotally connected .to

posedresilient members-whose outer ends) are anchored to said? drivingmemberand. whose inner ends are anchored to said driven member.

"'2.,A turn" indicatorglfor aircraftlrcomprisingl a cordance with therate of craft turn, means yieldably constraining precession of saidelement, an indicator, a driven member for actuating said indicator,means yieldably opposing movement of said driven member, a drivingmember actuated !by said rotor precession and pivotally connected tosaid driven member, and a pair of damping springs having their outerends anchored to said driving member and their inner ends anchored tosaid driven member to define an operative connection between saiddriving and driven members.

3. A turn indicator comprising a rotor mounted for spinning about oneaXis and a gimbal supporting the rotor for precession about a secondaxis perpendicular to said first axis, means yieldably constrainingprecession of said rotor, an indicator, a lever for actuating saidindicator, means yieldably opposing movement of said lever, a bracketsecured to said gimbal and pivotally connected to said lever, and a pairof opposed springs having their outer ends anchored to said bracket andtheir inner ends anchored to said lever to thereby define an operativeconnection between said gimbal and said indicator.

4. A turn indicator comprising a rotor mounted for spinning about oneaXis and a gimbal s'up porting the rotor for precession about a secondaxis perpendicular to said first axis, means controlled in accordancewith said precession, yielda-ble means comprising a dash-pot foropposing operation of said controlled means, a bracket secured to saidgimbal and pivotally connected to said controlled means, means connectedto said bracket for resiliently constraining precession of said rotor,and vibration damping means constituting a driving connection betweensaid bracket and said controlled means, said vibration damping meanscomprising a pair of opposed spring members having their out-er endsanchored to said bracket and their inner ends anchored to saidcontnolled means.

5. In a turn indicator, the combination comprising, a gyro rotor mountedfor spinning about one axis, a gimbal supporting the rotor forprecession about a second axis perpendicular to said first axis, meansfor resiliently constraining rotor precession, a driving member movablewith said gimbal, a lever pivotally connected to said member coaxialwith said gimbal axis, a pair of opposed resilient membersinterconnecting said member and said lever to oscillate the same aboutthe pivot connection upon movement of said gimbal due to gyro rotorprecession, and indicator means driven by said lever to indicate thedegree of gyro precession.

6. In a turn indicator, the combination comprising, a gyro rotor mountedfor spinning about one axis, a gimbal supporting the motor forprecession about a second axis perpendicular to said first axis, meansfor resiliently constraining rotor precession, a driving member movablewith said gimbal, a lever pivotally connected to said member coaxialwith sa g mb l ax s, a p r oi pposed resilient members having theirouter ends anchored to said member and their inner ends to said leverfor interconnecting said member and said lever to oscillate the sameabout the pivot connection upon movement of said gimbal due to gyrorotor precession, indicator means driven by said lever to indicate thedegree of gyro precession, and damper means connected to said lever.

7. A rate of turn responsive device comprising a gyro rotor mounted forspinning about one axis, a gimbal supporting the rotor for precessionabout a second axis perpendicular to said first axis, means forresiliently constraining precession of said rotor, a driving membermovable with said gimbal, a lever pivotally connected to said membercoaxially with said gimbal axis, a pair of opposed resilient membersinterconnecting said member and said lever to oscillate the same aboutthe pivot connection upon movement of said gimbal due to procession ofsaid gyro rotor, and means actuated by said lever in response to and inaccordance with the degree of gyro precession.

8. A rate of turn responsive device comprising a gyro rotor mounted forspinning about one axis, a gimbal supporting the rotor for precessionabout a second axis perpendicular to said first axis, means forresiliently constraining precession of said rotor, a driving membermovable with said gimbal, a lever pivotally connected to said membercoaxially with said gimbal axis, a pair of opposed resilient membershaving their outer ends anchored to said member and their inner ends tosaid lever for interconnecting said member and said lever to oscillatethe same about the pivotal connection upon movement of said gimbal dueto precession of said gyro rotor, means driven by said lever in responseto and in accordance with the degree of gyro precession, and dampingmeans connected to said lever.

JAMES E. BEVINS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 917,524 Bateman Apr. 6, 1909958,274 Owen May 17, 1910 1,165,529 Morse Dec. 28, 1915 1,706,201Drexler Mar. 19, 1929 1,842,824 Colvin et a1 Jan. 26, 1932 1,900,709Henderson Mar. 7, 1933 2,189,375 Sylvander Feb. 6, 1940 FOREIGN PATENTSNumber Country Date 75,906 Austria 1919 327,348 Germany 1920 698,675France 1931

